Slopeline approach light system



Get. 5, 1954 DAV|$ 2,691,150

SLOPELINE APPROACH LIGHT SYSTEM Filed March 25, 1954 2 Sheeis-Sheet 1 5O l5 0 0 o l4 0 g fi FIG. 3

/ INVENTOR a 4 JAMES E DAV/S Get. 5, 1954 J. E. DAVIS 2,691,150

SLOPELINE APPROACH LIGHT SYSTEM INVENT OR JAMES E DA W5 BY win/WATTRNEYs Patented Oct. 5, 1954 UNITED STATES PATENT OFFICE (Grantedunder Title 2365,)U. S. Code (1952),

6 Claims.

The invention described herein may be manu factured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

The present invention relates to a slopeline approach light system andmore particularly to slopeline approach light system which incorporatessingle dimension ground-plane and direction-of-flight elements into thethree dimensional elevation-and-centerline-deviation andhorizontal-and-distance elements.

The standard slopeline approach light system consists of two convergingrows of slopeline light units lying to the right and left of the runwayaxis, beginning 3000 feet from the runway threshold and ending at apoint 200-300 feet therefrom. The point of convergence of the two rowsoccurs near the ideal touchdown point on the runway centerline. Theindividual slopeline units are mounted in vertical planes perpendicularto the runway axis and are spaced at 100 foot intervals. The majordimension of each unit slopes toward the ideal glide path at an angle of45 degrees with respect to the plane of the runway. The transverselocation of the individual units is determined by the intersection ofthe two 45 degree planes, which pass through the ideal glide path, withthe local terrain. Three transverse bars were added to the originalslope line system to provide additional horizontal reference and toestablish three check points to inform the pilot of his distance fromthe runway threshold.

The disadvantage of the standard system is that neither the originalsystem nor the transverse bar additions provide a fixed ground planewith reference to the individual slope units, the only fixed referencefor the pilot being an imaginary line he draws from the base of one unitto the base of the next unit. The series of slope units tend to break upwhen the pilot is off of the ideal glide path and becomes confusingparticularly during low visibility approaches when he has only a fewunits of one side in view and is off the ideal glide path. Under theseconditions there is not enough ground plane and direction of flightinformation present and the pilot may make the wrong correction, therebynecessitating a new approach attempt. In the standard system there is nofixed reference for the slopeline units to oscillate around or pivotfrom. This leaves the pilot with the impression of a series of objectsin space with no tie point to indicate a ground plane or solid substanceahead on which to land the airplane.

The present invention overcomes the disadvantages of the prior knownsystems by incorporating single dimension ground-plane anddirection-of-flight elements into the three dimensionalelevation-andcenterline-deviation and horizontal-and-distance elements.This is accomplished by increasing the spacing between adjacent slopeunits and positioning individual lamp light units at short intervalsalong the ground plane therebetween, so as to form a straight line oflight units extending from the base of one slope unit away from thethreshold approximately half way towards the next slope unit. The singlelight units lie in the ground plane and provide artificial ground-planeand direction-offlight guidance even though the pilot may not readilyinterpret the elevation and lateral guidance afiorded by the slopeunits. The lines of light units provide fixed elements in the systemthat the top ends of the slope units can oscillate around and the bottomends can pivot from, thus giving the pilot a sensation of substancerather than merely something in space.

An object of the present invention is the provision of a slopelineapproach light system which includes tie points for the slopeline units.

Another object is to provide direction of flight guidance in a slopelineapproach light system.

A further object of the invention is the provision of well definedground plane guidance in a slopeline approach light system.

An additional object of the present invention is the provision of athree dimensional slopeline aproach light system which embodies singledimension ground-plane and line-of-fiight elements.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

Fig. 1 is a plan view of the threshold of a runway and an approach lightsystem according to the present invention.

Fig. 2 is an elevation view of the system of Fig. 1.

Fig. 3 is an elevation view of a slopeline light Fig. 1 shows thethreshold of a runway H and two rows of approach lights 12 and I3diverging away therefrom on either side of the runway centerline. Eachof the rows l2 and [3 consists of alternately arranged 45 degreeslopeline units I4 and groups of individual light units t5 and extendsapproximately 3000 feet from the runway threshold. The 45 degreeslopeline units are spaced approximately 200 feet apart and each groupof individual lights forms a line extending from the base of oneslopeline unit away from the runway threshold approximately halfway tothe next slopeline unit. Each group of individual lights usuallyconsists of seven lights spaced'l5 feet apart, the first one of which isalso positioned 15 feet from the base of a slopeline unit, the group oflights thus forms a line approximately 105 feet long. The spacingbetween individual lights or the number of individual lights in a groupmay be varied to satisfy the requirements of any individual approacharea, but the individual lights of each group must all be positioned ona line extending between the bottom lamps of adjacent slopeline units.

Fig. 2 shows an elevation View of one line of approach lights in whichthe approach area on which the row is positioned is flat. In this view,the individual light units are all in the same horizontal plane with thebottom lamps of adjacent slopeline units. If the approach area wereuneven and one slopeline unit at a higher elevation than the adjacentslopeline unit, the individual lights positioned therebetween would allbe mounted so as to be in the plane joining the bottom lamps of adjacentslopeline units. If the difference in elevation between adjacentslopeline units exceeds approximately 5 feet it may be necessary to addadditional lights to the group in order to retain the continuity of thesystem.

The 45 degree slopeline unit of Fig. 3 consists of a vertical upright Iton which is secured a crosspiece H at an angle of 45 degrees with thehorizontal. A plurality of lamps [S are spaced along the length of thecrosspiece. The slopeline units are arranged in pairs, one in each rowof lights, and the intersection of the extensions of the lines definedby the lamps on the crosspieces marks the location of the ideal glidepath.

The groups of individual light units provide direction of flight andground plane guidance which is not supplied by the slopeline units Asshown in Figs. 4-7, this guidance does not depend upon the position ofthe approaching aircraft, but exists for all positions during anappreach. When the approaching aircraft is on the ideal glidepath, thegroups of individual lights and the slopeline units merge into almostcontinuous straight rows. When the approaching aircraft is of; of theideal glidepath, the rows of light units become segmented and eachslopeline unit appears to pivot about its associated group of individuallight units. The slopeline units point inwardly when the aircraft ishigh on centerline, Fig. i, and outwardly when the aircraft is low oncenterline, Fig. 5. When the aircraft is not on the centerline and ishigh, Fig. 6, the farther row becomes segmented and the slopeline unitsof the nearer row point inwardly. As can be seen from 5, pilot low andto one side of the glidepath would see the slopeline units of thefarther row point outwardly and those of the near row overlap theadjacent groups of individual lights. As can be seen from Figs. 4-7, thelines formed by the individual light units engine aircraft and theytherefore provide two lines of approach lights for the pilot to followeven though he does not interpret the elevation guidance inherent in theslopeline units.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. An aircraft landing aid system including two straight rows oflighting elements converging towards the threshold of a landing strip,each of said rows comprising alternately positioned degree slopelinelight units and lines of spaced single light units, each of said linesof single light units extending from the base of one slopeline unit awayfrom the threshold approximately halfway to the next slopeline unit;whereby the lines of single light units provide fixed elements which thetops of the slopeline units oscillate around and the bottoms thereofpivot from.

2. An aircraft landing aid system including two straight rows oflighting elements converging towards the threshold of a landing strip,each of said rows comprising a plurality of 45 degree slopeline lightunits spaced at large intervals; a plurality of single light unitsspaced at short intervals positioned between each pair of slopelineunits, said plurality of single light units forming a line extendingfrom the base of one slopeline unit away from the threshold towards thenext slopeline unit; whereby each line of single light units forms afixed element about which the top of the associated slopeline unit canoscillate and from which the bottom thereof can pivot.

3. In an aircraft landing aid system including two straight rows ofspaced 45 degree slopeline light units converging towards the thresholdof landing strip, the improvement comprising a line of spaced singlelight units positioned between each pair of slopeline units, each lineof single light units extending from the base of one slopeline unit awayfrom the threshold approximately halfway to the next slopeline unit;whereby each line of single light units forms a fixed element aboutwhich the top of the associated slopeline unit oscillate and the bottomthereof can pivot.

4.. In a slopeline approach light system including two rows of 45 degreeslopeline light units converging towards the threshold of a landingstrip, the slopeline units of each row being spaced at large intervals,the improvement consisting of a plurality of single light units spacedat short intervals positioned between each pair of slopeline units, saidplurality of single units forming a line extending from the base of oneslopeline unit away from the threshold towards the next slopeline unit;whereby the lines of single units provide ground-plane and line-offiightguidance for an approaching aircraft.

5. A slopeline approach light system comprising two converging rows ofalternately positioned 45 degree slopeline units and lines of singleunits, each of said lines comprising a plurality of relatively closelyspaced single units, said slopeline units being spaced at twice thenormal interval with each line of single units extending from the baseof one slopeline unit in divergent fashion approximately halfway to thenext slopeline unit; whereby each line of single units forms a fixedelement about which the top of the associated 10 slopeline unit canoscillate and from which the bottom thereof can pivot.

6. In a standard slopeline approach light systerm including twoconvergent rows of 45 degree slopelinelight units with alternateslopeline units of each row removed, the improvement consisting of aplurality of relatively closely spaced single light imits positionedbetween each pair of slopeline units, each group of single units forminga line extending from the base of one slopeline unit in divergentfashion approximately halfway to the next slopeline unit; therebyproviding ground-plane and line-of-flight guidance for an approachingaircraft.

N 0 references cited.

